1. Field of the Invention
This invention relates to a dental X-ray film developing machine for developing one or more exposed dental X-ray films.
2Description of the Related Art
X-ray pictures of teeth have been used for the diagnosis and treatment of teeth in recent years. X-Ray photography of a tooth for obtaining its X-ray picture is effected by bringing an opaque dental X-ray film package, which contains an X-ray film sealed therein, into a diseased part within a mouth and then exposing the X-ray film to X-rays through the diseased part. By this X-ray photography, a latent image of the tooth is formed on the X-ray film. After completion of the X-ray photography, the X-ray film package is take out of the mouth and is then opened in a dark room or dark box to take out the X-ray film. The X-ray film thus taken out is processed for its development, for example, is developed, fixed and washed, whereby an X-ray picture of the thus-taken tooth is obtained on the X-ray film.
A variety of automatic developing machines has heretofore been proposed in order to perform the above development easily without labor. Many of such conventional developing machines have a structure that a developing bath, fixing bath, washing bath, etc. are provided, two sets of paired rollers are arranged in each bath, the individual rollers are rotated, an exposed X-ray film is nipped between the paired rollers in one set and is fed to the paired rollers in the other set, and this procedure is repeated successively in the developing bath, fixing bath and washing bath so as to conduct its development.
Among these automatic developing machines, an automatic developing machine permitting a size reduction of the overall structure has been proposed in Japanese Utility Model Publication No. 20115/1985. Some of its structural features will next be described with reference to FIG. 1.
FIG. 1 is a cross-sectional side view of the conventional automatic film developing machine proposed in the above publication. Numerals 1,2 indicate film feed rollers provided in a pair and letter a indicates their nip. Numeral 3,4 indicate film feed rollers provided in a pair in opposition to the film feed rollers 1,2. The nip of the film feed rollers 3,4 is also designated by a. The line connecting both nips a,a (i.e., the line shown by a phantom in FIG. 1) is substantially horizontal and the distance between the nips a,a is set slightly shorter than the length of a film as measured in the direction of its conveyance. There are also illustrated a catch pan 5 provided underneath the paired film feed rollers 1,2,3,4, a bottom wall 5a of the catch pan 5, and a raised central portion 5a' of the bottom wall 5a of the catch pan 5. Symbol 5b indicates both side walls of the catch pan 5. However, only one of the side walls 5b is shown in FIG. 1. A space 6 is formed by the film feed rollers 1,2,3,4, catch pan 5 and side walls 5b. Designated at numerals 7,8 are blades provided respectively in elastic contact with the rollers 2,4 in order to avoid leakage of a developer from the space 6. Numeral 9 indicates an overflow outlet formed through the side wall 5b . Designated at numeral 10 is a return pipe for collecting the developer overflowed to the outside from the space 6 and then recycling same to an unillustrated reservoir. Numeral 11 indicates a developer feed line for feeding the developer, which has been pumped up from the unillustrated reservoir, into the space 6.
When the developer is pumped up from the unillustrated reservoir and is then charged into the space 6 via the developer feed pipe 11, the level of the developer rises in the space 6 and eventually reaches the height of the overflow outlet 9. When the developer is fed further, the developer overflows through the overflow outlet 9 to the outside of the space 6. The thus-overflowed developer is then recycled to the unillustrated reservoir through the return pipe 10. As a result, the level of the developer is always maintained at the height of the overflow outlet 9. As shown in FIG. 1, the overflow outlet 9 is formed at a height higher than the line which connects the nips a,a to each other. When the film feed rollers 1,2,3,4 are rotated in a direction indicated by arrows and a film to be developed is fed between the film feed rollers 1,2 on the left-hand side as viewed in the drawing, the film passes from the film feed rollers 1,2 and then through the developer in the space, and is thereafter fed out of the space 6 while being pinched between the film feed rollers 3,4.
A processing unit adapted to perform processing of a film with a developer has been described above. Exactly the same processing unit can also be used for both fixing and washing. These processing units are arranged in the order of the developing unit, fixing unit and washing unit. Accordingly, a film can be developed surely without being bent. The developing machine can therefore be constructed into a relatively small size because it uses only two sets of paired rollers, which sets are arranged in an opposing relation, for feeding a film.
Although the above-described conventional automatic developing machine has various advantages, each processing unit requires the rollers 1-4 and catch pan 5. It is also necessary to provide, in addition to the space 6, the reservoir for the corresponding processing liquid as well as a pump and feed pipe (e.g., developer feed pipe 11) for feeding the processing liquid from the reservoir to the space 6. A further means is also required to collect the processing liquid overflowed from the space 6 and then to return it to the corresponding reservoir. The conventional automatic developing machine is therefore accompanied by such drawbacks that its structure is very large and complex and its manufacturing cost is high.